Worried about nothing at all

I never liked being alone since I was a little girl. If my parents were not around I would get really nervous and scared. I just felt very insecure and something was going to happen. Now I'm in my mid 20's and still when I'm alone I can't sleep and I get very nervous. I like being around people. So when my friend invited to a big dinner party that she was throwing I was excited to go. I knew I will get to meet new people. So I had been excited for the dinner the whole month until the day before the dinner. For some reason I got really nervous and worried to the point I was having a diarrhea. I tried to figure out what was bothering me but I couldn't. I had an anxiety attack the day of the dinner and I wasn't sure if I could even go like that. But when it was time I went and had a blast.

Do you ever get very anxious about nothing at all? like everything is going great but you are still worried?